Safety razor blade



Aug. 29, 1933. R. E. THOMPSON I SAFETY RAZOR 'BLADE Original Filed April 25, 1929 I71 venior iorfley Patented Aug. 29, 1933 UNITED STATES PATENT OFFICE SAFETY RAZOR BLADE Ralph E. Thompson, Brookllne, Masa, asslgnor to Gillette Safety Razor Company, Boston, Mass., a Corporation of Delaware Original application April 25, 1929, Serial No. 358,114. Divided and this application August 18, 1932. Serial No. 629,321

'1 Claims. (01. 30- 2) My invention relates to safety razors in which which it has already been flexed by the cap as a thin, flexible and elastic blade is removably awhole, and according to a familiar geometrisecured in a holder comprising a guard member cal principle the blade can notbe so flexed,

adapted to support the blade adjacent to its even slightly, without subjecting it to a greatly 5 longitudinal cutting edges and a transverselyincreased stress. In such a case the user'in- 00 curved cap member provided on opposite sides variably considers the unsatisfactory operation with parallel straight edges which engage the of his razor to be due to a defective blade, and blade adiacent to the longitudinal edges of the either continues to use the defective holder and latter and flex it transversely on the guard to flnd fault with the blades, or else discards the member as a fulcrum during the process of razor in favor of one of another make.

clamping the blade in the holder, so that, when To meet the difllculty above explained I have the razor is ready for use, the blade is maintaindevised an improvement which is applicable to ed in a transversely curved condition and subany razor of the construction hereinbefore de- Jected to a pronounced stress, particularly at its scribed and may be embodied therein without longitudinal edge portions. making any change except in the outline of the 70 The Gillette razor exemplifies the type of razor blade itself, my improved blade being given such which is described above, and the standard thicka contour that even if the blade-clamping cap ness of the flexible blade used in this razor is is bent at one or more of its corners, the posi- 0.006 inch. It is to blades of substantially this tioning of the blade edge under the flexing acorder of flexibility, and to such blades only, tion of the holder will not be aflected thereby, 75 that the present invention relates. For convennor will the blade be broken or cracked. In ience that type of razor will be referred to in this consequence, it becomes possible not only to specification and in the appended claims as obtain eflicient service from razors using such the Gillette type which term will imply the blades, even if the cap corners become bent,

entire description contained in the preceding but also to restore to satisfactory use a very paragraph. large number of such razors which havebeen In the use of such a razor, satisfactory operadiscarded or are now giving unsatisfactory servtion requires very accurate positioning of the ice. blade edge with respect to the guard, and con- My invention will be best understood and apsequently it is extremely desirable that the parts preciated from the following description of a which engage and flex the blade should retain, preferred embodiment thereof selected for purpermanently, the precise shapes and dimenposes of illustration and shown in the accomsions imparted to them when manufactured. panying drawing, in which- This is particularly true of the longitudinal Fig. 1 is a view in perspective of one form of straight edges of the blade-clamping cap, on razor containing my improved blade;

which the alignment and amount of exposure of Fig. 2 is a view in perspective of the cap and the blade edges depend, but inasmuch as these blade shown in Fig. 1, in position for assembling; cap edges are necessarily made thin, in order Fig. 3 is a sectional view illustrating in parto enable the cutting edge of the blade to reach tially assembled relation the parts shown in the skin when the razor is held at the proper Fig. 1; 95 shaving angle, they are veryeasily deformed, Fig. 4 is a view in perspective, on an enparticularly at the cap corners, to such an extent larged scale, showing a portion of the cap with as seriously to impair the efllciency of the razor. the blade applied thereto.

For example, the mere dropping of the razor, The blade-holding parts of the razor illusor of the cap alone, has frequently resulted in trated in Figs. 1, 2 and 3 of the drawing are of bending over a corner of the cap to an extent standard construction and comprise a guard 12 sufllcient, when the clamping pressure is applied provided with guard teeth 13 on each of its to the blade, to produce'an uneven edge expolongitudinal edges and with parallel shoulders sure or even to crack or break off a portion of 14 constituting fulcrums on which the flexible the blade itself. Such a result may occur even blade is flexed transversely when clamped in when the bending of the cap corner is so slight the holder, a transversely-curved cap 15 having that it is not likely to be noticed by the user, blade-positioning studs 16 and a threaded centhis being due to the fact that the pressure ter pin 17 projecting from its inner face and thereby applied to the blade tends to flex it adapted to pass respectively through perforalocally in a diflerent direction from that in tions in the guard member 12, a hollow handle 18 secured at one end to the guard member at the center of the latter, and a nut 19 adapted to turn freely in the handle 18 and having its inner end internally threaded to engage the pin 17, whereby the parts are clamped together. As in razors of this type, the internal apertures 23 provide edges arranged to engage the studs 16 thus holding the blade positively against rotation or angular displacement and with its sharpened edges properly located in the razor for shaving.

The longitudinal edges 10 of the cap 15 overhang and are parallel with the shoulders 14, and are located above channels '21 formed in the guard member 12 in position to underlie the cutting edges of the blade, so that when the blade is clamped in the holder its cutting edges are adjustably positioned and held over the channels 21, as described in U. S; Letters Patent No. 1,328,024, dated January 13, 1920.

The blade 22, shown best in Fig. 2, is or may be like the standard blade commonly used in razors of the type above described, in that it is of substantially uniform thickness transversely flexible, is sharpened on its parallel longitudinal edges to provide two cutting edges, has perforations 23 and 24 to receive the studs 16 and center pin 17 respectively, and is long enough at its center'to overhang the ends of the cap 15, the latter feature being desirablenot only to facilitate the removal of the blade from the cap but also to provide enough metal between the end perforations 23 and the ends of the blade to prevent cracking of the latter along its cen ter line.

In contrast to the standard blade previously referred to, however, my blade 22 is provided at each of its four corner portions with a reentrant recess 25 which bounds the corresponding end of the adjacent cutting edge and is so proportioned that when the blade is clamped in the holder these recesses span the respective corners of the cap 15 and provide clearance spaces of sufllcient size to receive said corners if bent over or otherwise distorted to any extent which is likely to result from accidental damage. Consequently my blade while being flexed transversely by the cap 15 is engaged only by those portions of the straight edges 10 of the cap which lie between the corresponding recesses 25, and can not be broken or cracked by a damaged cap corner either while being flexed or when flexed in final position in the holder.

Referring to Fig. 4,.it will be noted that the reentrant recesses 25 are each bounded internally by substantial fillets or inwardly-curved portions, the effect of which is to prevent excessive concentration of stress at these points when the blade is flexed and thereby avoid breakage on account of such stresses.

The blade of my invention is described and claimed in combination with a safety razor of well-known construction in my co-pending application, Serial No. 358,114, filed April 25, 1929,

of which the present application is a division.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. As a new article of manufacture, an elastic, transversely-flexible safety razor blade adapted for use in existing Gillette-type safety razors, said blade having unsharpened ends, being of uniform thickness, requiring external support on both sides for its cutting edge and being internally apertured to provide edges arranged to engage positioning and clamping means and hold the blade against angular displacement, and being also provided with reentrant recesses including a rounded portion at the inner angles thereof, located at the corner portions of the blade respectively and each extending both longitudinally and transversely of the blade to such an extent as to span the adjacent corner of the blade-clamping cap when assembled therewith, and to provide a clearance space of sufllcient area to receive a cap corner if bent, whereby said blade while being flexed or when clamped cannot be subjected to pressure by a bent cap corner and danger of breaking said blade or distorting its cutting edge is eliminated.

2. As a new article of manufacture, a razor blade of the Gillette type internally apertured to provide edges arranged to engage positioning means and hold the blade against angular displacement, and requiring external support on both sides for its cutting edge and of substantially uniform thickness and flexibility between its internal apertures and the cutting edges, said blade having reentrant recesses located in its corner portions providing clearance spaces of suflicient area to prevent clamping pressure by the corners of a blade holder, each recess having its inner corner curved in concave contour to avoid excessive stress concentration adjacent to'the perimeter of the recess.

3. As a new article of manufacture, an elastic, transversely-flexible razor blade adapted for use in existing Gillette type safety razors, said blade having unsharpened ends, being of uniform thickness and so thin as torequire external support on both sides thereof for substantially its full length to give rigidity to its cutting edge, and being internally apertured to provide edges arranged to engage positioning and clamping means and hold the blade against angular displacement, and being also provided with reentrant recesses located at its corner portions respectively and each extending both longitudinally and transversely of the blade to such an extent as to span the adjacent corner of the blade-clamping cap when assembled therewith, and provide a clearance space of suflicient area to receive a cap corner if bent, whereby said blade while being flexed or when clamped is relieved of the possibility of pressure from a bent cap corner, each of said recesses having an inner concave flllet shaped to prevent excessive stress concentration thereat.

4. As a new article of manufacture, an elastic transversely-flexible razor blade adapted for use in existing Gillette type safety razors, said blade being internally apertured to provide edges arranged to engage positioning means and hold the blade against angular displacement, and being of substantially uniform thickness and so thin as to require external support on both sides thereof for substantially its full length to give rigidity to its cutting edge, and being also provided with reentrant recesses located at its corner portions respectively and each extending both longitudinally and transversely of the blade to such an extent as to span the adjacent corners of the blade-clamping cap when assembled therewith and provide a clearance space of sumcient area to receive a cap corner if bent, whereby said blade while being flexed or when clamped is relieved of the possibility of pressure from a bent cap corner.

5. A flexible blade for use in safety razors of the type in which the blade is positioned between cap and guard members and is maintained transversely bent thereby when the parts are clamped together, said blade being of uniform thickness and so thin as to require external support on both sides for its cutting edge, being internally apertured to provide edges arranged to engage positioning means and hold the blade against angular displacement, and being cut away at each of its corners at a cutting edge thereof to such an extent as to provide clearance spaces of suflicient areas to receive the cap corners and thereby prevent clamping pressure by said corners.

6. A flexible blade for use in safety razors of the type in which the blade is positioned between cap and guard members and is maintained transversely bent thereby when the parts are clamped together, said blade being of uniform thickness and so thin as to require external support on both sides for its cutting edge, having unsharpened ends and being internally aperturned to provide edges arranged to engage positioning means and hold the blade against angular displacement, said blade being provided with cutaway portions at its corners at the cutting edges thereof to such an extent as to span the adjacent corners of the blade-clamping cap when assembled therewith thereby providing clearance spaces of suflicient area to each receive a cap corner if bent whereby said blade while being flexed or when clamped is relieved of the possibility of pressure from abent cap corner. I

7. A flexible blade for use in safety razors of the type in which the blade is positioned between cap and guard members and is maintained transversely bent thereby when the parts are clamped together, said blade being of uniform thickness and so thin as to require external support on both sides for its cutting edge, having unsharpened ends and being internally apertured to provide edges arranged to engage positioning means and hold the blade against angular displacement, said blade having portions cut away at the ends of its cutting edges to such an extent as to span the adjacent corners of the blade-clamping cap when assembled therewith thereby providing,

clearance spaces of suflicient area to each receive a cap corner if bent whereby said blade while being flexed or when clamped is relieved of the possibility of pressure from a bent cap cornerQ RALPH E. THOMPSON. 

